Maryland’s updated smoke alarm law continues to generate questions from homeowners and others who want to meet the requirements that went into effect Jan. 1, but have technical questions or are unsure how those requirements apply to their individual situations.

One electrician pointed out that if older houses are required under the law to be upgraded to a detector on each level of the house, but the owners are allowed to install battery-powered detectors, the detectors will not be linked so that they all sound off if one sounds off, as required in newer houses.

To get the alarms to “talk to each other,” he said, they would have to be hardwired.

Hardwired means permanently connected circuits, which would require electrical work. But the statute does not require hardwired alarms for older homes. One section of the updated statute specifies that “smoke alarms required in (one and two-family dwellings constructed before July 1, 1975) may be battery operated.”

Rather than repeat the language of the law adopted by the General Assembly, it may be helpful to look for practical information from emergency services websites.

The Carroll County Volunteer Emergency Services Association, www.ccvesa.org, advises that in homes where there are no smoke detectors, or detectors with 9-volt battery-operated alarms, the alarms must be replaced with sealed units that have 10-year lithium ion batteries. Owners of older houses could choose instead to install hardwired alarms rather than the battery models.

The idea is to get “more reliable smoke alarm coverage in older dwellings,” the website states.

How will homeowners know how old their smoke detectors are? The date of manufacture should appear on the inside of the detector, to the right of a warning notice in capital letters. If there is no date on the detector, the CCVESA says, “replace that alarm.”

Another reader asked if he must install a carbon monoxide detector as he upgrades his smoke alarms. The answer depends on how he heats the house and how old it is.

Maryland law requires carbon monoxide detectors only in houses where a building permit was issued for construction after Jan. 1, 2008, and then only in houses that use fossil fuel — wood, kerosene, natural gas, oil— for heating, ventilation, hot water or operating clothes dryers.

A carbon monoxide detector can be part of a combination smoke-carbon monoxide alarm, if the combined alarm meets building codes and smoke detection requirements set out in state law.

If your house falls under the requirements for carbon monoxide alarms, they must be installed in a central location outside each sleeping area, or, if you have a centralized alarm system with a “distinct and audible” sound — that is, one that would be very difficult to sleep through — then the carbon monoxide detectors should be installed within 25 feet of any household equipment that could produce the deadly gas.

The CCVESA website refers people who have additional questions to the Office of the State Fire Marshal, 410-653-8980.

Donna Engle is a retired Westminster attorney. Reach her with questions or feedback at 410-840-2354 or denglelaw@gmail.com. Her column, which provides legal information but not legal advice, appears on the second and fourth Sunday each month in Life & Times.